Jigsaw puzzle based on Featured Images on Commons(or any wiki). Person who completes the puzzle gets links to pages where the images used to read about it.

Slideshow of Featured pictures

Wordpress, Drupal, <Insert Your CMS> widget for Featured feeds to show content from Mediawiki (Wikipedia) sites on blogs / websites.

A simple text editor that supports input methods and web fonts. The output should correctly indicate the meta data of the language and possibly script. The MediaWiki Narayam and WebFonts extensions can be a point of reference.